基于数值反演的盾构斜穿施工对建筑桩基的影响分析

Analysis of the Influence of Shield Obliquely Crossing Construction on Pile Foundations Based on Numerical Inversion

以望海路盾构隧道南海花园二期范围段为依托工程,采用数值分析方法,分析了盾构施工对建筑桩基的扰动影响。分析结果及施工措施建议如下:(1)盾构施工距离桩基越近,对桩基的扰动越大,其中1^(#)、2^(#)、3^(#)位置桩基受盾构扰动影响最大。(2)盾构掘进开始至接近桩基期间,桩基变形量增幅最大,在掘进距离>100 m以后,各桩位移量变化幅度趋于稳定。(3)最大桩底竖向位移为-3.25 mm,最大水平位移为0.95 mm,桩顶最大竖向位移为-0.26 mm,最大水平位移为0.26 mm,均出现在1^(#)桩,且各桩顶受盾构扰动均小于桩底,变形量均满足规范要求,桩顶建筑物受施工影响在可控范围之内。(4)采用袖阀管对建筑周边地层预注浆,强化地层物理力学参数,加强桩基变形监测,严格控制并动态调整盾构掘进参数。

Based on the Nanhai Garden Phase II project of the Wanghai Road shield tunnel,the numerical analysis method was adopted to analyze the disturbance influence of shield construction on pile foundations.The analysis results and suggested construction measures are as follows:(1)The closer the shield construction is to the pile foundations,the greater the disturbance,with the pile foundations at positions 1^(#),2^(#),and 3^(#)being most affected.(2)During the period from the beginning of shield excavation to the pile foundation,the deformation of pile foundations increases the most,and after the excavation distance exceeds 100 m,the displacement change amplitude of each pile tends to stabilize.(3)The maximum vertical displacement of the pile bottom is-3.25 mm,and the maximum horizontal displacement is 0.95 mm;the maximum vertical displacement of the pile top is-0.26 mm,and the maximum horizontal displacement is 0.26 mm,all of which appear in the 1^(#)pile,and the pile top is disturbed by the shield.Less than the pile bottom,the deformation of the pile foundation meets the requirements of the specification,and the building on the top of the pile is within the controllable range affected by construction.(4)Adopt sleeve valve tubes for pre-injection grouting around the building,enhance the physical and mechanical properties of the strata,improve deformation monitoring of the pile foundations,and strictly control and dynamically adjust the parameters of the shield excavation.